Heraclitus

Heraclitus was a sixth century philosopher of Ephesus who is
regarded as the source of the influential thesis that everything is
(in) change or flux: this was expressed in the claim that "Upon those
that step into the same rivers different and different waters flow
.... It scatters and ... gathers ... it comes together and flows away
... approaches and departs"(fr. 12 and 91), popularly rephrased as
"you cannot step into the same river twice". Heraclitus was an
Ephesian nobleman and possibly renounced the kinship to his brother,
in favour of his educational career. The title of his book is
unknown, and only exists in fragments taken from other authors. This
makes the construction of his philosophical arguments a matter of
much dispute: Heraclitus has been called the "the Dark" philosopher
because of the obscurity of his extant texts, their apparent
contradictions and pessimism of the views which are expressed.

In Heraclitus's cosmology, the Logos is the governing principle of
all things, and remains the same for all things. It is never defined
but has various attributes. It is compared to an eternal fire, not
made by god but independently eternal. It is an object of possible
knowledge, operating according to regular patterns: its first
transformation is into fluid, but all things return to it for
regeneration into something else. Crucial to this account is the
transformation of opposites, in constant strife: Heraclitus uses the
image of lyre to explain how strife is able to combine the opposition
of forces in the world. "Harmony lies in the bending back, as for
instance of the bow and of the lyre". Thus the opposition results in
a unity, although it may not be apparent.

Heraclitus's theory of knowledge wavers between elitism and
conventionalism. He argues that wisdom is universal, likely in the
sense that all could have it, but distinguishes those who speak with
intelligence, and those who believe themselves to have unique
knowledge: these people are deluded. He believed that the
conventional wisdom should be upheld as one abides by law, but this
is partially because it is an instance of the divine law or logos,
which is the explanation of all things and divine. The divine is the
source and container of wisdom, of which "human nature" is devoid.
Wisdom's material source is fire. Heraclitus is ambiguous about the
senses: he says that sight is preferable to hearing, but also that
both are bad "witnesses".

Heraclitus moral and social philosophy emphasise temperance and
patriotism. Like Socrates, he exhorts humans to know themselves and
act with understanding. One should not indulge one's desires because
these harm the soul. Rather one should understand human nature, so
one does not act as those who are "asleep", functioning without
awareness. In one's political life, Heraclitus recommends fighting
for the laws as one would fight for a wall in the defense of the
city.

The legacy of Heraclitus is profound: his belief in the dynamic
nature of the physical world influenced Plato to argue that knowledge
of it would therefore be impossible, but since knowledge is possible,
it must be of something else: the unchanging transcendent forms. The
theory of oppositions as a prerequisite for change was adapted by
Aristotle in his own account of the physical world and the notions of
fire and night as cosmic forces may have influenced Empedocles to
hypothesise love and strife. In more recent philosophy, the strife of
opposites was emphasised by Hegel, who argued that out of the
opposites, a new synthesis inevitably arises in the progress of the
universe and its contents. Opposites to Aristotle, Hegel